The Alpin X project is carried out by the Zermatt Bergbahnen AG and aims at establishing a touristic link between Zermatt in Switzerland and Cervinia in Italy while facilitating access to the top of the Klein Matterhorn. This very challenging project is based on the construction of two new modern cableways joining each other at adjacent arrival stations founded in the 50-70° steep west face of the Klein Matterhorn, at 3’820.5 m a.s.l. Due to the steepness of the slope, construction works require extensive excavation and stabilization of the serpentinite bedrock and consequently to address various problematics related to superficial and shallow rock instabilities inside and outside the construction area. Moreover, the predominance of permafrost conditions required to adapt the techniques for the execution. While the first cableway from the north-side has been operational since winter 2018/2019, the second from the south is still under construction and will open in winter 2021/2022.
The high-altitude ski domain Matterhorn Paradise (Mattertal, Switzerland) spreads over 2200 m elevation from Zermatt at the bottom of the valley to the top of Klein Matterhorn at 3883 m a.s.l. (see figure 1). Since 1979 a double cabin cable-car provides an easy access to the summit for skiers, mountaineers and pedestrians throughout the entire year, making this place the highest point accessible by cable-car in the Alps. This unrivalled situation has led to a continuously growing number of visitors. In order to guarantee a touristic link with Italy and to increase transport capacity, the project Alpin Crossing [1], referred as Alpin X in the following, was initiated and the construction of two additional modern cableways, starting on both north and southeast sides of the Klein Matterhorn and joining on the summit area, was decided by the Zermatt Bergbahnen AG. Due to the limited space available on the summit ridge of the Klein Matterhorn, the locations of the two adjacent new arrival stations were chosen in the 50-70 degree steep west face, at the exit of an existing gallery at 3’821 m a.s.l. in (figure 1). At this location, the slope inclination made it necessary to carry out substantial multi-level excavations for the foundations of the envisioned buildings, leading to the setting up of a completely new rock geometry composed of several walls and terraces. In this context, geological and technical preliminary studies for the foundation of the two arrival stations were performed and results pointed out the need of perennial rock stabilization measures combined with a suitable excavation process, in order to protect the workers and facilities against rock instabilities during both the construction- and operation.